Proto-Indo-European Roots
| Root/Stem: | *gwóu- |
| Meanings: | a bull, a cow |
| Cognates: | |
| Hellenic | Greek bous, boos (a bull) |
| Italic | Latin bós, gen. bovis (a bull), Umbrian bum (acc. a bull), Volscian bim (gen. 'a bull'), Oscan Búvaianúd (a place name) |
| Celtic | Common Celtic *guhow- > Old Irish bó, gen. bai (a bull), Welsh buw, Old Breton bou |
| Indic | Sanskrit gaus (a bull) |
| Dardic & Nuristani | |
| Iranian | Avestan gáus' (a bull), Persian gáv (a cow) |
| Armenian | Armenian kov 'a cow' |
| Tocharic | Tocharic A ko, Tocharic B keu (a cow) |
| Thracian bonassos (a bull) | |
| Germanic | Common Germanic *ków- (a cow); > Old High German kuo (a cow), Old Saxon kó (a cow), Old English cú, Old Norse kýr Swedish ko, German Kuh, Dutch koe |
| Baltic | Common Baltic *guo- > Latvian guovs (a bull) |
| Slavic | Common Slavic *gove,do (a cow, a bull)
> Bulgarian & Serbian & Slovene govedo (a cow), Czech hovado, Slovak hovîdo, Upper Sorbian howjado, Lower Sorbian gowedo (a cow), Old Russian gov'ado |
| Notes: | A very ancient agricultural term, which could denote a cow when it was not domesticated yet. Nostratic cognates are also found for it: Semitic *g-w (a cow), Sumerian, Urartian & Hurritic gud, ngw (a bull) could be relatives. |